Influence of silicon content on the precipitation of secondary carbides and fatigue properties of a 5%Cr tempered martensitic steel

Denis Delagnes (1, 2) , Pascal Lamesle (2) , M. H. Mathon (3) , N Mebarki (2, 1) , Christophe Levaillant (2)

1 CEMES - Centre d'élaboration de matériaux et d'études structurales
2 CROMeP - Centre de Recherche Outillages, Matériaux et Procédés
3 LLB - UMR 12 - Laboratoire Léon Brillouin

in comparison with the conventional AISI H11 tool steel, which contains approximately 1 wt.% silicon, the modified steel AISI H11 (similar to 0.35 wt.% silicon) exhibits improved tensile and fatigue properties at 550 degrees C - the estimated tool surface temperature during the high-pressure injection of aluminium alloys. The effect of silicon on the stability of secondary carbides was studied using transmission electron microscopy and small-angle neutron scattering. Silicon has a considerable influence on the precipitation of secondary carbides. A higher volume fraction and density of small particles were observed in the low-silicon-grade steel, both after heat treatment and after fatigue testing. The final discussion focuses on the influence of silicon in the precipitation sequence. It is concluded that silicon has a detrimental effect as it shifts the secondary hardening peak towards lower tempering temperatures.

Mots clés: Isothermal fatigue; Silicon; 5%Cr martensitic steel; Tempering; Secondary carbides

Domaines: Matériaux

Denis Delagnes, Pascal Lamesle, M. H. Mathon, N Mebarki, Christophe Levaillant. Influence of silicon content on the precipitation of secondary carbides and fatigue properties of a 5%Cr tempered martensitic steel. Materials Science and Engineering: A, 2005, 394 (1-2), pp.435-444. ⟨10.1016/j.msea.2004.11.050⟩. ⟨hal-01715084⟩